The determination of errors in polarized neutron diffractometry

The polarized neutron method of determining the magnetic form factor of magnetic materials is examined in detail with special attention given to the way in which statistical errors are propagated. Because of the nonlinear relation between the polarizing efficiency of a crystal and the magnetic scattering length, the usual methods of linear error theory will not work. However, this difficulty can be circumvented by using the nonlinear formulas directly. The statistical error analysis is applied to the practical problem of how long one should count on a particular Bragg peak. This time will depend on the ratio of the magnetic to the nuclear scattering lengths, p/b, and on the accuracy with which the beam polarizations and flipping efficiencies have been determined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33028/1/0000412.pd

Association between physical activity motives and type of physical activity in children

Abstract: Objectives: Motives for participating in a specific type of physical activity (PA) may differ across PA type in youth. We studied the relationship between PA motives and type of PA engaged in by youth. Design: Cross-sectional analysis using data from the Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study. Method: 802 students age 10-11 years from 17 primary schools in New-Brunswick, Canada completed a questionnaire that collected data on type of PA participated in (individual, group-based, organized, non-organized), PA motives (enjoyment, social affiliation, competence, fitness/health, appearance) and attainment of PA guidelines (60 minutes of moderate-to-vigorous PA per day). The associations between PA motives and PA type and between PA motives and attainment of PA recommendations were assessed in multilevel logistic regression models. Results: Endorsing enjoyment motives was associated with participation in organized PA (Odds Ratio, 95% Confidence Interval: 1.54, 1.24-1.91). Competence motives were associated with participation in group-based PA (1.27, 1.11-1.46) and achievement of PA recommendations (1.95, 1.37-2.78). Conclusion: Targeting enjoyment and competence motives may be associated with increased participation in organized and group-based PA as well as with an increased likelihood of meeting PA guidelines in youth

EFFECTS OF PUROMYCIN, ACETOXYCYCLOHEXIMIDE AND ACTINOMYCIN D ON PROTEIN SYNTHESIS IN GOLDFISH BRAIN *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65427/1/j.1471-4159.1966.tb10284.x.pd

Understanding the Results of Multiple Linear Regression: Beyond Standardized Regression Coefficients

Multiple linear regression (MLR) remains a mainstay analysis in organizational research, yet intercorrelations between predictors (multicollinearity) undermine the interpretation of MLR weights in terms of predictor contributions to the criterion. Alternative indices include validity coefficients, structure coefficients, product measures, relative weights, all-possible-subsets regression, dominance weights, and commonality coefficients. This article reviews these indices, and uniquely, it offers freely available software that (a) computes and compares all of these indices with one another, (b) computes associated bootstrapped confidence intervals, and (c) does so for any number of predictors so long as the correlation matrix is positive definite. Other available software is limited in all of these respects. We invite researchers to use this software to increase their insights when applying MLR to a data set. Avenues for future research and application are discussed

Rapid inverting of the polarization of a neutron beam using large amplitude oscillating magnetic fields

During the course of designing and constructing a pulsed-neutron-polarization-inverter (PNPI) to be used in the study of magnetic excitations in solids, it was necessary to re-examine the oscillating field method of magnetic resonance in the region where the amplitude of the rf field B1 is comparable to the dc field B0. It is found that the phase of the rf field at the instant the neutron enters the spatial region of the field becomes an increasingly important considerations asB1/B0 becomes comparable to 1. Analog and digital computer solutions are given for the equations of motion of the neutron's magnetic moment in the presence of various field configurations important in the construction of a PNPI.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32785/1/0000158.pd

The state, civil society and social rights in contemporary Russia

peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=fjcs21peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=fjcs2

Algebraic characteristic classes for idempotent matrices

This paper contains the algebraic analog for idempotent matrices of the Chern-Weil theory of characteristic classes. This is used to show, algebraically, that the canonical line bundle on the complex projective space is not stably trivial. Also a theorem is proved saying that for any smooth manifold there is a canonical epimorphism from the even dimensional algebraic de Rham cohomology of its algebra of smooth functions onto the standard even dimensional de Rham cohomology of the manifold

Magnetic correlations and quantum criticality in the insulating antiferromagnetic, insulating spin liquid, renormalized Fermi liquid, and metallic antiferromagnetic phases of the Mott system V_2O_3

Magnetic correlations in all four phases of pure and doped vanadium sesquioxide V_2O_3 have been examined by magnetic thermal neutron scattering. While the antiferromagnetic insulator can be accounted for by a Heisenberg localized spin model, the long range order in the antiferromagnetic metal is an incommensurate spin-density-wave, resulting from a Fermi surface nesting instability. Spin dynamics in the strongly correlated metal are dominated by spin fluctuations in the Stoner electron-hole continuum. Furthermore, our results in metallic V_2O_3 represent an unprecedentedly complete characterization of the spin fluctuations near a metallic quantum critical point, and provide quantitative support for the SCR theory for itinerant antiferromagnets in the small moment limit. Dynamic magnetic correlations for energy smaller than k_BT in the paramagnetic insulator carry substantial magnetic spectral weight. However, the correlation length extends only to the nearest neighbor distance. The phase transition to the antiferromagnetic insulator introduces a sudden switching of magnetic correlations to a different spatial periodicity which indicates a sudden change in the underlying spin Hamiltonian. To describe this phase transition and also the unusual short range order in the paramagnetic state, it seems necessary to take into account the orbital degrees of freedom associated with the degenerate d-orbitals at the Fermi level in V_2O_3.Comment: Postscript file, 24 pages, 26 figures, 2 tables, accepted by Phys. Rev.

The Puromycin Route to Assess Stereo- and Regiochemical Constraints on Peptide Bond Formation in Eukaryotic Ribosomes

We synthesized a series of puromycin analogues to probe the chemical specificity of the ribosome in an intact eukaryotic translation system. These studies reveal that both d-enantiomers and β-amino acid analogues can be incorporated into protein, and provide a quantitative means to rank natural and unnatural residues. Modeling of a d-amino acid analogue into the 50S ribosomal subunit indicates that steric clash may provide part of the chiral discrimination. The data presented provide one metric of the chiral and regiospecificity of mammalian ribosomes

Evolution of Thermal Response Properties in a Cold-Activated TRP Channel

Animals sense changes in ambient temperature irrespective of whether core body temperature is internally maintained (homeotherms) or subject to environmental variation (poikilotherms). Here we show that a cold-sensitive ion channel, TRPM8, displays dramatically different thermal activation ranges in frogs versus mammals or birds, consistent with variations in these species' cutaneous and core body temperatures. Thus, somatosensory receptors are not static through evolution, but show functional diversity reflecting the characteristics of an organism's ecological niche